bridgehead -
an area in hostile territory that has been captured and is held awaiting further troops and supplies; "an attempt to secure a bridgehead behind enemy lines"; "the only foothold left for British troops in Europe was Gibraltar"
bridgehead -
An area of ground on the enemy's side of a bridge, especially one that needs to be taken and defended in order to secure an advance.
bridgehead -
Either of the two atoms in different parts of a molecule that are connected by a bridge.
Wikipedia
A bridgehead (also 'Bridge-head'; French tête-de-pont) is a military fortification that protects the end of a bridge that is closest to the enemy. The term has been generalized in colloquial usage to refer to any kind of defended area that is extended into hostile territory – also called a foothold or, incorrectly, a beachhead – in particular the area on the farside of a defended river bank or a segment of a lake or riverine coastline, such as the Bridge at Remagen. The term is especially applied when such a territory is initially seized by an amphibious assault with the tactical intent of establishing a supply line across the geographic barrier feature to allow further operational manoeuvring.
